THE Duchess of Cambridge has spoken of the power of art to change people's lives in a speech to celebrate the work of Oxford-based charity The Art Room.

Kate told an audience of 250 artists, schoolchildren and supporters of The Art Room, of which she is patron, that it felt "incredibly special" to be at the National Portrait Gallery in London last night to celebrate the work of the charity.

The Art Room, which uses art to increase children's self-confidence and independence, was marking its 11th anniversary and launching a new fundraising campaign at the event.

Kate, wearing a duck-egg blue empire-line Emilia Wickstead cocktail dress and dusky blue heels, said: "I am a firm believer in the power of art to make a difference and The Art Room is doing that on a daily basis.

"We all stand here tonight to celebrate this wonderful work.

"I hope that you will join me in congratulating The Art Room and their supporters on these extraordinary achievements.

"As patron of The Art Room, I feel immense pride to see the amazing work that they are doing but I also feel hugely excited to look to a future with more Art Rooms, where many more challenging and vulnerable children will be helped."

The Duchess, who wore her hair half up, is also patron of the National Portrait Gallery - and a portrait of her is currently on display at the venue.

Kate, an art history graduate, said: "I always love coming to the National Portrait Gallery so to be here tonight for an evening to celebrate The Art Room makes it feel incredibly special.

"When I have been fortunate enough to join Art Room sessions, I have been overwhelmed by the transformational impact they have.

"Vulnerable children flourish in the safe havens that The Art Room provide."

The Duchess spoke to children who use The Art Room facilities in London and Oxford and accompanied some of them on a private tour of a Man Ray exhibition at the gallery.

Six months pregnant Kate, whose bump was clearly showing in her cocktail dress, asked the children if they had been to the gallery before and if they went on many visits.

The Art Room currently has six centres at schools in Oxfordshire and London, and two more - in Ealing and Edinburgh - are set to open.

Juli Beattie, founder director of the charity, which helps children from the ages of five to 16, told those at the event: "This is a moving evening for all of us. I think we have done a lot of hard work.

"To see so many people here, in the Duchess's presence, is overwhelming."

She said the children enjoyed being shown around by National Portrait Gallery director Sandy Nairne.

The Art Room launched a new fundraising campaign, Pledge For The Future, at the National Portrait Gallery event.